The invention relates to a stand aid with at least one sitting surface that is arranged on a support frame and can be adjusted between a load-free rest position and at least one sitting position in which it is subjected to the load of a user, whereby adjustment is carried out by means of the support frame which automatically readjusts the sitting surface back into the rest position by means of a resetting mechanism as soon as the load of the sitting surface is removed.
Such stand aids are widely used to relieve the strain of standing in situations where sitting to perform work tasks, for instance at machines, in tool machining, or behind sales counters, is not possible. To allow the strain of standing to be relieved, customary stand aids now in use have a support frame on which at least one sitting surface is affixed. These stand aids, equipped with mechanical or gas-spring-supported height adjustment, can be either stationary or foldable; they generally share the disadvantage that, when not in use, they are in the way or must be put away in a separate place in order to keep the work area free for circulation.
A standard type of stand aid is known, for instance, from DE 26 42 112 A1. This known stand aid is designed as a single-leg seat, of which the swivel leg that supports the sitting surface is secured to a foot part by way of a resetting mechanism in the form of a spring device. The stand aid is unfolded by having the user sit on the sifting surface and hold it in this unfolded seat position by means of his weight. The sifting position is thus defined by the fact that the user supports himself with the legs or feet on the ground and thus restricts the adjusting angle of the pivot leg. The result is a weak working posture in the sifting position, because the sifting position has to be secured in every direction by the user. The continuous support of the stand aid in the sifting position, however, places a constant burden on the user, and consequently such a stand aid is only partially effective at relieving the strain of standing.
The aim of the invention, therefore, is to design a stand aid of the type mentioned at the outset, in such a way that it takes over as much of the strain of standing and/or sitting as possible.
The invention provides a solution to this aim which is characterized in that the support frame is provided with a pivoting mechanism, can be anchored on a bottom and is provided with at least one support leg. The support frame rests on said leg in the sifting position in order to receive the vertical forces and define the adjusting angle at the bottom.
This inventive design of the stand aid for the first time allows a stable sitting position in which the user is not required to support the entire vertical forces with his legs. While diverting the support weight to the bottom, the stand aid also serves to restrict the adjusting angle of the stand aid, resulting in a defined and thus stable sifting position. Such a stable sitting position clearly increases safety in the use and operation of the stand aid designed in accordance with this invention, because problems such as buckling the legs forward are no longer possible.
In addition this results in a stand aid that, after removal of the user""s weight, returns to a rest position that takes up less space than in the sitting position. Such a stand aid is moved into position only when actually being used, so that the work area is otherwise kept free.
The bottom anchoring of the support frame in this design provides the counterweight for the pivoting support frame.
The resetting mechanism, designed to replace the stand aid when not in use back into rest position by means of the support frame, in one realization of the invention, is designed as a replacement spring connected with the support frame. Such a replacement spring has the advantage that it is designed as a spiral spring secured onto a pivot axis and thus upon pivoting of the stand aid is tensioned into the sitting position.
In an alternative embodiment, the replacement mechanism is designed as a counterweight with a pivoting connection to the sitting area, which counterweight in the sitting position of the stand aid is steered out of its end position in order to pre-tension the support frame in the direction toward the unburdened resting position. This design of the replacement mechanism as a counterweight can also take the form whereby the pivotable support frame is stored off-center so that it returns independently to the rest position in the absence of weight on the sitting surface when pivoted into sitting position.
According to another practical embodiment of the invention it is proposed that the sitting surface should be adjustable by means of the support frame between an unburdened rest position and two sitting positions.